How many pillows do you need?

Here’s the funny thing, though: it’s actually a trick question. Most people really only need one pillow.

Pillows play an important role in helping you get a good night’s sleep. To enjoy restful sleep, you need to keep your spine in alignment from your pelvis to your neck. Your mattress and pillow work together, along with your sleep position, to achieve this. If your spine becomes misaligned during sleep, you’ll wake up with aches and pains the next morning. Plus, the sleep you do have will be restful, as well.

While most people only need one pillow, it needs to be the “right” pillow. Below we’ll review what that looks like, and offer a few exceptions to the one pillow rule.

The one true pillow you need

The right pillow should support your sleeping position, keeping your spine aligned while you sleep.

A pillow cannot be too high or too low. It has to be just the right height. Otherwise, it forces your neck out of alignment with the rest of your spine.

In the bedding industry, the pillow’s height is called pillow loft. Pillow lofts generally fall into one of three categories: low loft (3 inches or less), medium lot (3 to 5 inches high), and high loft (5 inches or more). Different lofts are recommended for different sleep positions. Your body type can also influence which loft you prefer. People with larger heads and/or wide shoulders tend to prefer higher lofts for their added comfort, while people with smaller heads and/or narrow shoulders sleep just fine with lower lofts.

Find your sleep position below to discover the one true pillow you need. We’ve suggested the appropriate loft for each, too:

Side sleepersneed one thick pillow to sleep on. A high loft is recommended. Memory foam pillows can be a great option. For proper alignment, the thickness, or height, of the pillow should match the length from the end of their shoulder to their neck.

Back sleepers need a thinner pillow, just thick enough to keep the neck aligned with the spine while you sleep. Low to medium loft pillows are best. Pillows with a divot for the head are ideal, since they provide more height beneath the neck with a concave area for the head.

Stomach sleepers need an extremely thin, low-loft pillow, or perhaps no pillow at all. If the pillow is too high, it uncomfortably forces their neck up and backward toward their spine. The advantage of sleeping without a pillow is that it helps stomach sleepers keep their spine as straight as possible. Alternately, a pillow with a divot for the head (similar to what you see with a massage table) enables them to sleep facing down, ensuring optimal spinal alignment while still giving them room to breathe.

Did you find you need a new pillow for your preferred sleeping position? Take your pick from the best-reviewed pillows.

When one pillow isn’t enough

Sometimes, one pillow isn’t enough. There are circumstances where people may feel better supported by multiple pillows. Here they are:

Side sleepers may find comfort from an additional pillow placed in between their knees. It should be a thin pillow, just wide enough to keep your pelvis straight during sleep. Or, this could take the form of a body pillow that fits between their knees, but extends long enough for them to wrap their arms around.

Back sleepers may relieve lower back pain with a thin pillow beneath their knees. This is especially helpful when there is a gap between the small of the back and the mattress surface. By placing the pillow beneath the knees, it elevates the knees slightly, encouraging the lower back to sink deeper into the mattress in response and thus straighten the spine.

Pregnant sleepers are often recommended to use body pillows. During pregnancy, expecting mothers deal with a variety of new and uncomfortable aches and pains. A supportive body pillow helps keep them on their side, while additional pillows propped behind the back, beneath the knees, and below the stomach, provide extra support. Side sleeping is recommended for pregnant women to ensure fetal health and blood flow.

Sleepers with chronic back pain can find relief by sleeping on their side and placing thin pillows beneath their knees and/or their ribs.

A quick note on multiple pillows: Some people like to layer multiple thinner pillows to achieve the effect of one thicker pillow. They figure, it’s the same height, so it’s probably the equivalent support. Unfortunately, they couldn’t be more wrong. Head pillows are not designed to be layered on top of each other. Fillers can shift during sleep, or the entire pillow can tip off to the side. For best results, stick to one, good pillow.

Additional resources

Want to learn more about how pillows affect your sleep? Check out the articles below.